1. Field of the Invention
The present invention pertains to a fluid conduit that has an expansion joint, and more particularly to a fluid conduit with an expansion joint having packing material between first and second tube sections.
2. Description of Related Art
Many materials expand as their temperature increases, and contract with decreasing temperatures. Generally, metals have large thermal expansion coefficients which indicate that they undergo a relatively large expansion for a given change in temperature. Consequently, the need for expansion joints has long been recognized.
There are a large variety of expansion joints known in the art. Many such conventional expansion joints may be classified as of the bellows type expansion joint. In such expansion joints, the material, which is often a metal, has a corrugated or bellows-like structure. As the temperature of the expansion joint changes, the bellows-like structure can expand and contract like a bellows, or in a spring-like manner. Such expansion joints have disadvantages that they result in fatigue and thus cracks and other damage to the joint. This is a particularly severe problem when the material is brittle, when there are frequent cycles of temperature changes, and with large temperature variations.
An expansion joint which has a bellows-like, or spring-like, structure is disclosed in Mutchler (U.S. Pat. No. 4,072,329). The device of Mutchler has the disadvantages of the bellows-type expansion joints in that its bellow-like, or spring-like, structure undergoes fatigue as the joint is cycled through temperature changes during operation. Furthermore, the device of Mutchler is designed to carry gases which are at relatively low temperatures such as 500.degree. F.